[PATCH v3 16/27] function_graph: Move set_graph_function tests to shadow stack global var
From: Steven Rostedt
Date: Mon Jun 03 2024 - 15:11:08 EST
From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
The use of the task->trace_recursion for the logic used for the
set_graph_function was a bit of an abuse of that variable. Now that there
exists global vars that are per stack for registered graph traces, use that
instead.
Link: https://lore.kernel.org/linux-trace-kernel/171509105520.162236.10339831553995971290.stgit@devnote2
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
include/linux/trace_recursion.h | 5 +----
kernel/trace/trace.h | 32 ++++++++++++++++++----------
kernel/trace/trace_functions_graph.c | 6 +++---
kernel/trace/trace_irqsoff.c | 4 ++--
kernel/trace/trace_sched_wakeup.c | 4 ++--
5 files changed, 29 insertions(+), 22 deletions(-)
diff --git a/include/linux/trace_recursion.h b/include/linux/trace_recursion.h
index 24ea8ac049b4..02e6afc6d7fe 100644
--- a/include/linux/trace_recursion.h
+++ b/include/linux/trace_recursion.h
@@ -44,9 +44,6 @@ enum {
*/
TRACE_IRQ_BIT,
- /* Set if the function is in the set_graph_function file */
- TRACE_GRAPH_BIT,
-
/*
* In the very unlikely case that an interrupt came in
* at a start of graph tracing, and we want to trace
@@ -60,7 +57,7 @@ enum {
* that preempted a softirq start of a function that
* preempted normal context!!!! Luckily, it can't be
* greater than 3, so the next two bits are a mask
- * of what the depth is when we set TRACE_GRAPH_BIT
+ * of what the depth is when we set TRACE_GRAPH_FL
*/
TRACE_GRAPH_DEPTH_START_BIT,
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index f06b5ddd3580..73919129e57c 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -898,11 +898,16 @@ extern void init_array_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops
extern int allocate_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops);
extern void free_fgraph_ops(struct trace_array *tr);
+enum {
+ TRACE_GRAPH_FL = 1,
+};
+
#ifdef CONFIG_DYNAMIC_FTRACE
extern struct ftrace_hash __rcu *ftrace_graph_hash;
extern struct ftrace_hash __rcu *ftrace_graph_notrace_hash;
-static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
+static inline int
+ftrace_graph_addr(unsigned long *task_var, struct ftrace_graph_ent *trace)
{
unsigned long addr = trace->func;
int ret = 0;
@@ -924,12 +929,11 @@ static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
}
if (ftrace_lookup_ip(hash, addr)) {
-
/*
* This needs to be cleared on the return functions
* when the depth is zero.
*/
- trace_recursion_set(TRACE_GRAPH_BIT);
+ *task_var |= TRACE_GRAPH_FL;
trace_recursion_set_depth(trace->depth);
/*
@@ -949,11 +953,14 @@ static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
return ret;
}
-static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace)
+static inline void
+ftrace_graph_addr_finish(struct fgraph_ops *gops, struct ftrace_graph_ret *trace)
{
- if (trace_recursion_test(TRACE_GRAPH_BIT) &&
+ unsigned long *task_var = fgraph_get_task_var(gops);
+
+ if ((*task_var & TRACE_GRAPH_FL) &&
trace->depth == trace_recursion_depth())
- trace_recursion_clear(TRACE_GRAPH_BIT);
+ *task_var &= ~TRACE_GRAPH_FL;
}
static inline int ftrace_graph_notrace_addr(unsigned long addr)
@@ -979,7 +986,7 @@ static inline int ftrace_graph_notrace_addr(unsigned long addr)
return ret;
}
#else
-static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
+static inline int ftrace_graph_addr(unsigned long *task_var, struct ftrace_graph_ent *trace)
{
return 1;
}
@@ -988,17 +995,20 @@ static inline int ftrace_graph_notrace_addr(unsigned long addr)
{
return 0;
}
-static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace)
+static inline void ftrace_graph_addr_finish(struct fgraph_ops *gops, struct ftrace_graph_ret *trace)
{ }
#endif /* CONFIG_DYNAMIC_FTRACE */
extern unsigned int fgraph_max_depth;
-static inline bool ftrace_graph_ignore_func(struct ftrace_graph_ent *trace)
+static inline bool
+ftrace_graph_ignore_func(struct fgraph_ops *gops, struct ftrace_graph_ent *trace)
{
+ unsigned long *task_var = fgraph_get_task_var(gops);
+
/* trace it when it is-nested-in or is a function enabled. */
- return !(trace_recursion_test(TRACE_GRAPH_BIT) ||
- ftrace_graph_addr(trace)) ||
+ return !((*task_var & TRACE_GRAPH_FL) ||
+ ftrace_graph_addr(task_var, trace)) ||
(trace->depth < 0) ||
(fgraph_max_depth && trace->depth >= fgraph_max_depth);
}
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 7f30652f0e97..66cce73e94f8 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -160,7 +160,7 @@ int trace_graph_entry(struct ftrace_graph_ent *trace,
if (!ftrace_trace_task(tr))
return 0;
- if (ftrace_graph_ignore_func(trace))
+ if (ftrace_graph_ignore_func(gops, trace))
return 0;
if (ftrace_graph_ignore_irqs())
@@ -247,7 +247,7 @@ void trace_graph_return(struct ftrace_graph_ret *trace,
long disabled;
int cpu;
- ftrace_graph_addr_finish(trace);
+ ftrace_graph_addr_finish(gops, trace);
if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
@@ -269,7 +269,7 @@ void trace_graph_return(struct ftrace_graph_ret *trace,
static void trace_graph_thresh_return(struct ftrace_graph_ret *trace,
struct fgraph_ops *gops)
{
- ftrace_graph_addr_finish(trace);
+ ftrace_graph_addr_finish(gops, trace);
if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 5478f4c4f708..fce064e20570 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -184,7 +184,7 @@ static int irqsoff_graph_entry(struct ftrace_graph_ent *trace,
unsigned int trace_ctx;
int ret;
- if (ftrace_graph_ignore_func(trace))
+ if (ftrace_graph_ignore_func(gops, trace))
return 0;
/*
* Do not trace a function if it's filtered by set_graph_notrace.
@@ -214,7 +214,7 @@ static void irqsoff_graph_return(struct ftrace_graph_ret *trace,
unsigned long flags;
unsigned int trace_ctx;
- ftrace_graph_addr_finish(trace);
+ ftrace_graph_addr_finish(gops, trace);
if (!func_prolog_dec(tr, &data, &flags))
return;
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 49bcc812652c..130ca7e7787e 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -120,7 +120,7 @@ static int wakeup_graph_entry(struct ftrace_graph_ent *trace,
unsigned int trace_ctx;
int ret = 0;
- if (ftrace_graph_ignore_func(trace))
+ if (ftrace_graph_ignore_func(gops, trace))
return 0;
/*
* Do not trace a function if it's filtered by set_graph_notrace.
@@ -149,7 +149,7 @@ static void wakeup_graph_return(struct ftrace_graph_ret *trace,
struct trace_array_cpu *data;
unsigned int trace_ctx;
- ftrace_graph_addr_finish(trace);
+ ftrace_graph_addr_finish(gops, trace);
if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
return;
--
2.43.0